Anterior throttle carburetor



Filed Feb. l2, 1935 INI 'ENTOR WJLLARD B. GOODMAN Patented Feb. 9, 1937 PATENT OFFICE ANTERIOR CABBURETOB wma-ain. ranma, N. J., asignar to Wright' Aeronautical Corporation, a corporation of New York f applicaties reti-nary 12, 193s, serial No. 6,155 As claims. (ci. 12s-119) acteristics automatically compensated for supercharger pressure rise.

15 A further object is to provide an anterior throttle carburetor wherein the throttle is 'subject to air flow only, and thus to remove the throttle icing hazard present when this member is cooled by the evaporating fuel. I Y

The anterior location of the throttle subjects the jet to vacuum under part-throttle conditions and to compensate for this, the carburetor of this invention incorporates an air vmetering Avalve operated from the pressure drop across the throttle.

Other objects and advantages lwill be obvious from the following description, with reference to the gure, which represents an inverted `type of carburetor secured to the inlet I0 of an enginesupercharger il which delivers to the en- .gine through the usual inlet pipes, one of which is indicated tically at l2. Y

' The carburetor body has a main-down-draftpassage extending from the entrance I4 to the supercharger intake 'll'forming a choke or venl turi IE above which there is disposed a throttle Il. The jets are indicated as holes 2l. drilled through the side of the venturi ii and communicatingby way of a Vpassage 22 with an air- 40 bleed channel 24 into which a main fuel chan-v nel 2B delivers. Air enters the air-bleed vchannel 24 through an atinospliericpassageA 2l and via an air-bleed valve 3l which is provided with anairmeteringportn. I' 4.5A Fuel is suppliedto the carburetorthrough a 24 viaa conventional oat valve which controls the fuel level in a oat vchamber' 38 by meansoiaoatintheusualway.

' Metering of thefuelquantity'is through a metering valve 42 which is equippedwith a stop 44 comprising an idling adjustment.

The metering valve 42 is operated by va, diaphragm 46, the under side of which is connected withthepressuresideofthesuperchargeras 56 by a connection 48 shown as communicating with the inlet pipe I2. The upper side of this diaphragm is connected by a passage tothe super-charger entrance near l0, between the carburetor and the supercharger, the lower end of l this passage being-indicated at 52. Thisvsuper- 5 charger inlet pressure is also eiective on the upper side of an air-bleed valve diaphragm 54 by way of a connecting pipe 56 while the' lower side of thisdiaphragm 54 is connected to the v atmospheric carburetor air entrance passage 28 10 through holes 58. y

4The fuelmetering valve 42 is equipped, above its diaphragm 46, with a spring 59 tending to keep the valve against the idling stop 44, whilea ltension spring 60 tends to keep the air-bleedvlii valve 30 in its downward position.

The float chamber is provided with an at-v mospheric vent 62 and the venturi vI6 is provided with a heating jacket 64.

It will be'seen from the-abovel that the fuel 20 metering valve 42 is controlled by the diierential in pressure existing between the supercharger inlet I0 beneath the throttle I8 and the inlet pipe i2. Inother words, the diaphragm 46 is subject to a pressure proportional to the 25 supercharger pressure rise acting in- .oppositionv to the spring 59, to increase the fuel passing area at the fuel metering valve.

The air-bleed valve 3U is operated by the differential in pressure between the; supercharger 30 inlet I0 and the atmospheric carburetor inlet. In other words, the air-bleedvis, controlled by the l pressure drop across lthe throttle. Thus, by' changing therelative contours of the air-bleed port 32 and of the metering valve 42, the fuel-air 35 ratio characteristicsvof the carburetor may be set as desired, thus greatly reducing the number of setting adjustments required as compared to many of the carburetors in the prior art.

It should be noted that the pressure rise through a supercharger varies with the atmos pheric density. That is to say, with other conditions unchanged, the pressure rise becomes less as the altitude increases. Thus, the pressure bey neath the diaphragm 4i through the connection 45 4l from the manifold I2 will decrease with alti? tude, lowering the metering valve 42 and reducing the fuel quantity as necessary to automatically compensate for the richening eect of altitude. so This automatic air density correction is also eiective as to changes in density due to changes in Aatmospheric temperature, thus automatically compensating for both air temperature and density variations for which purpose manual mix- 'usually resorted to.

.ng automatic priming.

While I have described my invention in detail in ,itsA present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without delxarting from the spirit or scope thereof. `I aim in the appended claims to cover all such modifications and changes.

What is claimed is:

1. A carburetor for an engine having a supercharger including in combination, a fuel jet, 'a throttle anterior to said jet with respect to said supcrcharger, a fuel metering valve, and means to control said valve responsively to the pressure difference created by said supercharger.

2. A carburetor for an engine having a superchaxger including a fuel metering valve, means responsive to the pressure rise through .said

supercharger to control the opening of said valve,

4. A carburetorforanenginehavingauper-Y charger creating air pressure rise, including incombination, a jet, a throttle creating an air pressuredrop at said iet, andA fuel and air-bleed metering means operated respectively from laid rise anddrop.

5. Aearburetorforanenginehavinganinduetion system-including amanifold, a venturi. a throttle at the air entrance side ofsaid venturi. means for bleeding fuel and air into said venturi;

and means responsive to pressure differencesbe-l tween different portions of said induction system e for controlling the air-bleed and fuel do'.

6. A'carburetor for an engine. having a supercharger onv the downstream side thereof, said carburetor having a venturi and a fuel jet. thereat; an air-bleed fuel iet *adapted to direct airv and .fuel to said venturLand means controlled by the .pressure difference between the ambient airandthepressuresideofsaidsuperchargerfor governing the rate o( fuel flow through said airsaid valve responsive in its action to the diiler.A

ence in pressure between the upstream side of said throttle and thev downstream side of said venturi.

8. A carburetor for an engine including in comi bnation. a' venturi having a low pressure neck,

an air-bleed fuel nonle opening into said neck', a v

throttle on the upstream aide of said venturi. an airbleed valve, and means for controlling said valve responsive in its action to the pressure difference between iheupstream side of said throttle and the downstream side thereof.v at a point remote from said venturi neck.

; WIILARD B. GOODHAN. 

